/* ==========================================================================
   File Converter - Premium Design System
   Modern, clean, beautiful gradients
   ========================================================================== */

/* Google Fonts */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

/* CSS Variables */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #818cf8;
    --secondary: #06b6d4;
    --secondary-light: #22d3ee;
    --accent: #10b981;
    --accent-light: #34d399;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;

    --bg: #fafbfe;
    --bg-subtle: #f1f5f9;
    --surface: #ffffff;
    --surface-elevated: #ffffff;
    --border: #e2e8f0;
    --border-light: #f1f5f9;

    --text-primary: #0f172a;
    --text-secondary: #64748b;
    --text-muted: #94a3b8;

    --shadow-xs: 0 1px 2px rgba(0,0,0,0.04);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.04);
    --shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
    --radius-2xl: 32px;
    --radius-full: 9999px;

    --transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Dark Mode */
[data-theme="dark"] {
    --bg: #0a0e1a;
    --bg-subtle: #0f1629;
    --surface: #151b2e;
    --surface-elevated: #1a2236;
    --border: #1e293b;
    --border-light: #1a2236;

    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-muted: #64748b;

    --shadow-xs: 0 1px 2px rgba(0,0,0,0.3);
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.4), 0 1px 2px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.5), 0 2px 4px -2px rgba(0,0,0,0.4);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.5), 0 4px 6px -4px rgba(0,0,0,0.4);
    --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.5), 0 8px 10px -6px rgba(0,0,0,0.4);
    --shadow-glow: 0 0 60px rgba(99, 102, 241, 0.2);
}

/* Reset */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: var(--bg);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
}

.hidden {
    display: none !important;
}

/* Background Pattern */
body::before {
    content: '';
    position: fixed;
    inset: 0;
    background:
        radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.06) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(6, 182, 212, 0.05) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(16, 185, 129, 0.03) 0%, transparent 60%);
    pointer-events: none;
    z-index: 0;
}

[data-theme="dark"] body::before {
    background:
        radial-gradient(circle at 20% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(6, 182, 212, 0.06) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(16, 185, 129, 0.04) 0%, transparent 60%);
}

/* ==========================================================================
   Layout
   ========================================================================== */

.page-wrapper {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    max-width: 1400px;
    margin: 0 auto;
    padding: 1.5rem;
    position: relative;
    z-index: 1;
}

.main-content {
    flex: 1;
    max-width: 800px;
    width: 100%;
}

/* ==========================================================================
   Theme Toggle
   ========================================================================== */

.theme-toggle {
    position: fixed;
    top: 1.25rem;
    right: 1.25rem;
    z-index: 1000;
    width: 44px;
    height: 44px;
    border-radius: var(--radius-md);
    border: 1.5px solid var(--border);
    background: var(--surface);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.theme-toggle:hover {
    transform: scale(1.08);
    box-shadow: var(--shadow-md);
    border-color: var(--primary);
}

/* ==========================================================================
   Ad Containers
   ========================================================================== */

.ad-container {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 0.75rem;
}

.ad-top {
    background: var(--bg-subtle);
    min-height: 90px;
    border-bottom: 1px solid var(--border-light);
}

.ad-bottom {
    background: var(--bg-subtle);
    min-height: 90px;
    margin-top: 2rem;
    border-top: 1px solid var(--border-light);
}

.ad-sidebar,
.ad-sidebar-right {
    width: 160px;
    min-height: 600px;
    display: none;
    position: sticky;
    top: 5rem;
    align-self: flex-start;
}

.ad-placeholder {
    background: var(--bg-subtle);
    border: 1.5px dashed var(--border);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-muted);
    font-size: 0.8rem;
    font-weight: 500;
    width: 100%;
    height: 100%;
    min-height: 90px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.ad-sidebar .ad-placeholder,
.ad-sidebar-right .ad-placeholder {
    min-height: 600px;
}

@media (min-width: 1200px) {
    .ad-sidebar,
    .ad-sidebar-right {
        display: block;
    }
}

/* ==========================================================================
   Header
   ========================================================================== */

.header {
    text-align: center;
    padding: 3rem 1.5rem 2rem;
    margin-bottom: 1.5rem;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.875rem;
    margin-bottom: 0.75rem;
}

.logo-icon {
    width: 52px;
    height: 52px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.3);
}

.logo-icon svg {
    width: 28px;
    height: 28px;
}

.logo h1 {
    font-size: 2.25rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 400;
}

.header-badges {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    margin-top: 1.25rem;
}

.badge {
    padding: 0.4rem 1rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    box-shadow: var(--shadow-xs);
}

.badge-privacy {
    background: rgba(16, 185, 129, 0.08);
    border-color: rgba(16, 185, 129, 0.2);
    color: #059669;
}

.badge-free {
    background: rgba(99, 102, 241, 0.08);
    border-color: rgba(99, 102, 241, 0.2);
    color: var(--primary);
}

[data-theme="dark"] .badge {
    background: var(--surface-elevated);
}

/* ==========================================================================
   Upload Section
   ========================================================================== */

.upload-section {
    margin-bottom: 2rem;
}

.upload-area {
    background: var(--surface);
    border: 2px dashed var(--border);
    border-radius: var(--radius-xl);
    padding: 3.5rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition-slow);
    position: relative;
    overflow: hidden;
}

.upload-area::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.02), rgba(6, 182, 212, 0.02));
    opacity: 0;
    transition: var(--transition-slow);
}

.upload-area:hover {
    border-color: var(--primary-light);
    box-shadow: var(--shadow-glow);
    transform: translateY(-2px);
}

.upload-area:hover::before {
    opacity: 1;
}

.upload-area.dragover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.04);
    transform: scale(1.01);
    box-shadow: var(--shadow-glow);
}

.upload-icon {
    width: 72px;
    height: 72px;
    margin: 0 auto 1.25rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1), rgba(6, 182, 212, 0.1));
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
}

.upload-content h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.375rem;
    color: var(--text-primary);
}

.browse-link {
    color: var(--primary);
    font-weight: 600;
    cursor: pointer;
}

.supported-formats {
    margin-top: 1.5rem;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.max-size {
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 0.25rem;
}

.paste-hint {
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 0.5rem;
}

.paste-hint kbd {
    background: var(--bg-subtle);
    border: 1px solid var(--border);
    padding: 0.15rem 0.45rem;
    border-radius: 5px;
    font-family: 'Inter', sans-serif;
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.privacy-note {
    color: var(--success);
    font-size: 0.8rem;
    margin-top: 0.75rem;
    font-weight: 500;
}

/* ==========================================================================
   Privacy Trust Bar
   ========================================================================== */

.privacy-trust-bar {
    margin-bottom: 2rem;
    padding: 0 1rem;
}

.trust-items {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.75rem;
}

.trust-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: rgba(16, 185, 129, 0.06);
    border: 1px solid rgba(16, 185, 129, 0.15);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.trust-icon {
    font-size: 1rem;
}

.trust-text strong {
    color: var(--text-primary);
}

/* ==========================================================================
   Privacy Promise Section
   ========================================================================== */

.privacy-promise {
    margin: 3rem 0 2rem;
    padding: 2.5rem 1.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
}

.privacy-promise h2 {
    text-align: center;
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.promise-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.promise-item {
    text-align: center;
    padding: 1.5rem 1rem;
    background: var(--bg-subtle);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
    transition: var(--transition);
}

.promise-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--success);
}

.promise-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.promise-item h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.promise-item p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* ==========================================================================
   FAQ Section
   ========================================================================== */

.faq-section {
    margin: 2rem 0;
    padding: 2.5rem 1.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
}

.faq-section h2 {
    text-align: center;
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.faq-list {
    max-width: 700px;
    margin: 0 auto;
}

.faq-item {
    padding: 1.25rem 0;
    border-bottom: 1px solid var(--border-light);
}

.faq-item:last-child {
    border-bottom: none;
}

.faq-item h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.faq-item p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* Footer Privacy */
.footer-privacy-badge {
    margin-bottom: 1rem;
    padding: 0.5rem 1.25rem;
    background: rgba(16, 185, 129, 0.08);
    border: 1px solid rgba(16, 185, 129, 0.15);
    border-radius: var(--radius-full);
    display: inline-block;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--success);
}

.footer-privacy-statement {
    margin-top: 0.75rem;
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ==========================================================================
   Why Privacy Section
   ========================================================================== */

.why-privacy-section {
    margin: 3rem 0 2rem;
    padding: 2.5rem 1.5rem;
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.03), rgba(245, 158, 11, 0.03));
    border: 1px solid rgba(239, 68, 68, 0.1);
    border-radius: var(--radius-xl);
}

.why-privacy-section h2 {
    text-align: center;
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.why-privacy-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.25rem;
}

.why-privacy-card {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    text-align: center;
}

.why-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.why-privacy-card h3 {
    font-size: 1rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
}

.why-privacy-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.why-privacy-cta {
    text-align: center;
    margin-top: 2rem;
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--success);
}

/* ==========================================================================
   Testimonials Section
   ========================================================================== */

.testimonials-section {
    margin: 2rem 0;
    padding: 2.5rem 1.5rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
}

.testimonials-section h2 {
    text-align: center;
    font-size: 1.75rem;
    font-weight: 800;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.25rem;
}

.testimonial-card {
    background: var(--bg-subtle);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-light);
}

.testimonial-stars {
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}

.testimonial-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
    font-style: italic;
    margin-bottom: 0.75rem;
}

.testimonial-author {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
}

/* ==========================================================================
   Content Page Styles (Blog, Transparency, etc.)
   ========================================================================== */

.page-content-section {
    padding: 4rem 0;
}

.content-page {
    max-width: 800px;
    margin: 0 auto;
}

.content-page h2 {
    font-size: 2rem;
    font-weight: 800;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.content-page h3 {
    font-size: 1.25rem;
    font-weight: 700;
    margin: 2rem 0 0.75rem;
    color: var(--text-primary);
}

.content-page p {
    font-size: 0.95rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.content-page ul {
    margin: 0.75rem 0 1rem 1.5rem;
    color: var(--text-secondary);
}

.content-page li {
    margin-bottom: 0.5rem;
    line-height: 1.6;
}

.content-updated {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 2rem;
}

/* Transparency Steps */
.transparency-step {
    padding: 1rem 1.25rem;
    background: var(--bg-subtle);
    border-radius: var(--radius-md);
    margin-bottom: 0.75rem;
    border-left: 3px solid var(--primary);
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.transparency-step strong {
    color: var(--text-primary);
}

.tech-list, .no-list {
    list-style: none;
    margin-left: 0;
}

.tech-list li, .no-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-light);
}

/* Compliance Cards */
.compliance-card {
    background: var(--bg-subtle);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    margin-bottom: 1.5rem;
    border: 1px solid var(--border);
}

.compliance-card p:first-child {
    margin-bottom: 0.75rem;
}

.compliance-card ul {
    margin-left: 1rem;
}

/* Comparison Table */
.comparison-table {
    margin: 2rem 0;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}

.comparison-header {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    background: var(--primary);
    color: white;
    font-weight: 700;
    font-size: 0.9rem;
}

.comparison-row {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;
    border-bottom: 1px solid var(--border-light);
}

.comparison-row:last-child {
    border-bottom: none;
}

.comparison-header > div,
.comparison-row > div {
    padding: 0.75rem 1rem;
    font-size: 0.85rem;
}

.comp-feature {
    font-weight: 600;
    color: var(--text-primary);
}

.comp-us {
    color: var(--success);
    background: rgba(16, 185, 129, 0.04);
}

.comp-them {
    color: var(--text-secondary);
    background: rgba(239, 68, 68, 0.02);
}

.comparison-cta {
    text-align: center;
    margin-top: 2.5rem;
}

.comparison-cta h3 {
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

/* Blog Grid */
.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
    margin-top: 2rem;
}

.blog-card {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.blog-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.blog-date {
    font-size: 0.75rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.blog-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    margin-top: 0;
}

.blog-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.75rem;
}

.blog-tag {
    display: inline-block;
    padding: 0.25rem 0.6rem;
    background: rgba(99, 102, 241, 0.08);
    border-radius: var(--radius-full);
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--primary);
}

/* Benchmark Grid */
.benchmark-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.25rem;
    margin: 2rem 0;
}

.benchmark-card {
    background: var(--surface);
    padding: 1.5rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
}

.benchmark-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.benchmark-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.benchmark-item {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-light);
    font-size: 0.85rem;
}

.benchmark-item:last-child {
    border-bottom: none;
}

.benchmark-label {
    color: var(--text-secondary);
}

.benchmark-value {
    font-weight: 700;
    color: var(--success);
}

.benchmark-note {
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 1.5rem;
}

.hero-formats {
    margin: 1.5rem 0;
}

/* ==========================================================================
   Convert Section
   ========================================================================== */

.convert-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: 2rem;
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.file-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-subtle);
    border-radius: var(--radius-lg);
    margin-bottom: 1.5rem;
    border: 1px solid var(--border-light);
}

.file-icon {
    font-size: 2rem;
}

.file-details {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-weight: 600;
    color: var(--text-primary);
    word-break: break-all;
    font-size: 0.95rem;
}

.file-type {
    color: var(--text-secondary);
    font-size: 0.8rem;
    margin-top: 0.125rem;
}

.format-selector {
    margin-bottom: 1.5rem;
}

.format-selector label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.format-select {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-family: inherit;
    background: var(--surface);
    color: var(--text-primary);
    cursor: pointer;
    transition: var(--transition);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%2364748b' stroke-width='2'%3E%3Cpath d='M6 9l6 6 6-6'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 1rem center;
}

.format-select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.convert-btn {
    width: 100%;
    padding: 1rem 2rem;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
}

.convert-btn:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
}

.convert-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    box-shadow: none;
}

.btn-spinner {
    animation: spin 1s linear infinite;
}

.reset-btn {
    width: 100%;
    margin-top: 0.75rem;
    padding: 0.75rem;
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.reset-btn:hover {
    background: var(--bg-subtle);
    color: var(--text-primary);
    border-color: var(--text-muted);
}

/* ==========================================================================
   Operations
   ========================================================================== */

.operations-container {
    margin-bottom: 1.5rem;
}

.operations-container label {
    display: block;
    margin-bottom: 0.75rem;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.operations-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 0.75rem;
}

.operation-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.375rem;
    padding: 1rem 0.75rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--surface);
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
}

.operation-btn:hover {
    border-color: var(--primary-light);
    background: rgba(99, 102, 241, 0.04);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.operation-btn.active {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.08);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.op-icon {
    font-size: 1.5rem;
}

.op-name {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.85rem;
}

.op-desc {
    font-size: 0.7rem;
    color: var(--text-secondary);
    line-height: 1.3;
}

.operation-options {
    margin-bottom: 1.5rem;
    padding: 1.25rem;
    background: var(--bg-subtle);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--primary);
    border: 1px solid var(--border);
    border-left: 3px solid var(--primary);
}

.operation-options label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.option-input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-family: inherit;
    background: var(--surface);
    color: var(--text-primary);
    transition: var(--transition);
}

.option-input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.option-input::placeholder {
    color: var(--text-muted);
}

.operation-options small {
    display: block;
    margin-top: 0.5rem;
    color: var(--text-secondary);
    font-size: 0.8rem;
}

.file-count {
    color: var(--text-muted);
    font-size: 0.75rem;
    margin-top: 0.25rem;
    word-break: break-all;
}

/* Quick Presets */
.quick-presets {
    margin-bottom: 1.5rem;
}

.quick-presets label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 0.9rem;
}

.presets-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.preset-btn {
    padding: 0.4rem 0.85rem;
    background: var(--surface);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-secondary);
}

.preset-btn:hover {
    border-color: var(--primary);
    color: var(--primary);
    background: rgba(99, 102, 241, 0.04);
}

/* ==========================================================================
   Progress Section
   ========================================================================== */

.progress-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: 2.5rem 2rem;
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.progress-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.progress-step {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.5rem;
    opacity: 0.35;
    transition: var(--transition);
}

.progress-step.active {
    opacity: 1;
}

.progress-step.complete {
    opacity: 1;
}

.step-icon {
    width: 52px;
    height: 52px;
    border-radius: 50%;
    background: var(--bg-subtle);
    border: 2px solid var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    transition: var(--transition);
}

.progress-step.active .step-icon {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-color: transparent;
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.35);
    animation: pulse 2s infinite;
}

.progress-step.complete .step-icon {
    background: var(--success);
    border-color: transparent;
    color: white;
}

.step-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.progress-step.active .step-label {
    color: var(--primary);
}

.progress-step.complete .step-label {
    color: var(--success);
}

.progress-arrow {
    font-size: 1.25rem;
    color: var(--text-muted);
}

.progress-bar-container {
    width: 100%;
    height: 6px;
    background: var(--bg-subtle);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 1rem;
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--primary), var(--secondary), var(--accent));
    border-radius: 3px;
    transition: width 0.4s cubic-bezier(0.16, 1, 0.3, 1);
    background-size: 200% 100%;
    animation: shimmer 2s infinite linear;
}

@keyframes shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

.progress-status {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

/* ==========================================================================
   Download Section
   ========================================================================== */

.download-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: 3rem 2rem;
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    text-align: center;
    animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.success-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.25rem;
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.1), rgba(52, 211, 153, 0.1));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
}

.download-section h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--success);
}

.download-message {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* Countdown Timer */
.countdown-container {
    margin: 1.5rem auto;
    max-width: 280px;
    text-align: center;
}

.countdown-label {
    font-size: 0.8rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.countdown-number {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--success), #059669);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
    margin-bottom: 0.5rem;
}

.countdown-bar-container {
    width: 100%;
    height: 4px;
    background: var(--bg-subtle);
    border-radius: 2px;
    overflow: hidden;
}

.countdown-bar {
    height: 100%;
    width: 100%;
    background: var(--success);
    border-radius: 2px;
    transition: width 1s linear, background 0.3s ease;
}

.expiry-notice {
    color: var(--text-muted);
    font-size: 0.8rem;
    margin-top: 0.75rem;
    font-weight: 500;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2.5rem;
    background: linear-gradient(135deg, var(--success), #059669);
    color: white;
    text-decoration: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    box-shadow: 0 4px 14px rgba(16, 185, 129, 0.35);
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(16, 185, 129, 0.45);
}

.convert-another-btn {
    display: inline-block;
    margin-top: 1.5rem;
    padding: 0.65rem 1.5rem;
    background: transparent;
    color: var(--text-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    font-family: inherit;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.convert-another-btn:hover {
    background: var(--bg-subtle);
    color: var(--text-primary);
}

/* ==========================================================================
   Error Section
   ========================================================================== */

.error-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-xl);
    padding: 3rem 2rem;
    box-shadow: var(--shadow-sm);
    margin-bottom: 2rem;
    text-align: center;
    animation: slideUp 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

.error-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 1.25rem;
    background: rgba(239, 68, 68, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2.5rem;
}

.error-section h2 {
    font-size: 1.75rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--error);
}

.error-message {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.retry-btn {
    padding: 0.85rem 2.5rem;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.35);
}

.retry-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.45);
}

/* ==========================================================================
   Features Section
   ========================================================================== */

.features-section {
    margin-bottom: 2.5rem;
}

.features-section h2 {
    text-align: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
    gap: 1rem;
}

.feature {
    background: var(--surface);
    padding: 1.5rem 1.25rem;
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.feature:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.feature-icon {
    width: 48px;
    height: 48px;
    margin: 0 auto 0.75rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08), rgba(6, 182, 212, 0.08));
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
}

.feature h3 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.375rem;
    color: var(--text-primary);
}

.feature p {
    font-size: 0.8rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* ==========================================================================
   Formats Section
   ========================================================================== */

.formats-section {
    margin-bottom: 2.5rem;
}

.formats-section h2 {
    text-align: center;
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.formats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1rem;
}

.format-category {
    background: var(--surface);
    padding: 1.25rem;
    border-radius: var(--radius-lg);
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.format-category:hover {
    border-color: var(--primary-light);
    box-shadow: var(--shadow-sm);
}

.format-category h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.375rem;
    color: var(--text-primary);
}

.format-category p {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.format-category small {
    display: block;
    margin-top: 0.375rem;
    color: var(--text-muted);
    font-size: 0.7rem;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.footer {
    text-align: center;
    padding: 2.5rem 1rem;
    border-top: 1px solid var(--border);
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.footer-links {
    margin-top: 0.5rem;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--primary);
}

/* ==========================================================================
   Modals
   ========================================================================== */

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
    animation: fadeIn 0.2s ease;
}

.modal-content {
    background: var(--surface);
    border-radius: var(--radius-xl);
    padding: 2.5rem;
    max-width: 560px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-xl);
    position: relative;
    animation: slideUp 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

.modal-content h2 {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 1.25rem;
    color: var(--text-primary);
}

.modal-content p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.7;
    font-size: 0.95rem;
}

.modal-close {
    position: absolute;
    top: 1.25rem;
    right: 1.25rem;
    background: var(--bg-subtle);
    border: none;
    width: 32px;
    height: 32px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 1rem;
    transition: var(--transition);
}

.modal-close:hover {
    background: var(--border);
    color: var(--text-primary);
}

/* ==========================================================================
   History
   ========================================================================== */

.history-section {
    margin-top: 2rem;
    padding: 1.25rem;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
}

.history-section h3 {
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
    color: var(--text-primary);
}

.history-list {
    list-style: none;
    max-height: 180px;
    overflow-y: auto;
}

.history-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-light);
    font-size: 0.8rem;
}

.history-item:last-child {
    border-bottom: none;
}

.history-item .file-name {
    color: var(--text-primary);
    flex: 1;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-weight: 500;
}

.history-item .file-meta {
    color: var(--text-muted);
    font-size: 0.7rem;
    margin-left: 0.5rem;
}

.history-clear {
    background: none;
    border: none;
    color: var(--error);
    font-size: 0.75rem;
    font-weight: 500;
    cursor: pointer;
    margin-top: 0.5rem;
    font-family: inherit;
}

.history-clear:hover {
    text-decoration: underline;
}

/* ==========================================================================
   Landing Page Styles (shared)
   ========================================================================== */

.landing-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    background: rgba(250, 251, 254, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-light);
}

[data-theme="dark"] .landing-nav {
    background: rgba(10, 14, 26, 0.88);
}

.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0.75rem 1.5rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    text-decoration: none;
    font-weight: 700;
    font-size: 1.2rem;
    color: var(--text-primary);
}

.nav-logo-icon {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
}

.nav-logo-icon svg {
    width: 18px;
    height: 18px;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.9rem;
    transition: var(--transition);
}

.nav-links a:hover {
    color: var(--primary);
}

/* Hero */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    padding: 6rem 1.5rem 4rem;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(6, 182, 212, 0.1) 0%, transparent 50%),
        radial-gradient(ellipse at 60% 80%, rgba(16, 185, 129, 0.06) 0%, transparent 50%);
}

[data-theme="dark"] .hero-bg {
    background:
        radial-gradient(ellipse at 20% 50%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(6, 182, 212, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse at 60% 80%, rgba(16, 185, 129, 0.08) 0%, transparent 50%);
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
}

.hero-badge {
    display: inline-block;
    padding: 0.45rem 1.15rem;
    background: rgba(99, 102, 241, 0.08);
    border: 1px solid rgba(99, 102, 241, 0.15);
    border-radius: var(--radius-full);
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 1.5rem;
    letter-spacing: 0.06em;
    text-transform: uppercase;
}

.hero h1 {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.25rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 560px;
    margin: 0 auto 2.5rem;
    line-height: 1.7;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-bottom: 2.5rem;
}

.stat {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 1.75rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.625rem;
    padding: 1rem 2.25rem;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    text-decoration: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    transition: var(--transition);
    box-shadow: 0 4px 16px rgba(99, 102, 241, 0.35);
}

.hero-cta:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 24px rgba(99, 102, 241, 0.45);
}

.hero-cta svg {
    transition: transform 0.3s ease;
}

.hero-cta:hover svg {
    transform: translateX(4px);
}

/* Floating cards */
.hero-visual {
    position: absolute;
    inset: 0;
    z-index: 0;
    pointer-events: none;
}

.floating-card {
    position: absolute;
    background: var(--surface);
    padding: 0.75rem 1.25rem;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    font-size: 1.25rem;
    border: 1px solid var(--border);
}

.card-1 {
    top: 20%;
    left: 5%;
    animation: float 6s ease-in-out infinite;
}

.card-2 {
    top: 30%;
    right: 8%;
    animation: float 6s ease-in-out infinite 2s;
}

.card-3 {
    bottom: 25%;
    left: 10%;
    animation: float 6s ease-in-out infinite 4s;
}

/* Section shared */
.section-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.section-title {
    text-align: center;
    font-size: 2.25rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    letter-spacing: -0.02em;
}

.section-subtitle {
    text-align: center;
    font-size: 1.05rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
}

/* Steps */
.how-section {
    padding: 6rem 0;
}

.steps-grid {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
}

.step-card {
    background: var(--surface);
    padding: 2.5rem 2rem;
    border-radius: var(--radius-xl);
    text-align: center;
    border: 1px solid var(--border);
    position: relative;
    max-width: 260px;
    transition: var(--transition);
}

.step-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.step-number {
    position: absolute;
    top: -14px;
    left: 50%;
    transform: translateX(-50%);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.8rem;
}

.step-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.step-card h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 0.375rem;
    color: var(--text-primary);
}

.step-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

.step-connector {
    font-size: 1.5rem;
    color: var(--text-muted);
    opacity: 0.4;
}

/* Format tags */
.formats-showcase {
    padding: 4rem 0;
    background: var(--bg-subtle);
}

.format-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.625rem;
}

.format-tag {
    padding: 0.45rem 1.1rem;
    background: var(--surface);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 0.85rem;
    color: var(--text-primary);
    transition: var(--transition);
}

.format-tag:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.output-tag {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border-color: transparent;
}

/* Upload hero */
.upload-hero {
    padding: 6rem 0;
}

/* Features */
.features-showcase {
    padding: 6rem 0;
    background: var(--bg-subtle);
}

.features-grid-landing {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 1.25rem;
}

.feature-card {
    background: var(--surface);
    padding: 2rem;
    border-radius: var(--radius-xl);
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.feature-icon-wrap {
    width: 64px;
    height: 64px;
    margin: 0 auto 1rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.08), rgba(6, 182, 212, 0.08));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
}

.feature-card h3 {
    font-size: 1.05rem;
    font-weight: 700;
    margin-bottom: 0.375rem;
    color: var(--text-primary);
}

.feature-card p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Footer */
.landing-footer {
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 4rem 0 2rem;
}

.footer-inner {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

.footer-brand {
    margin-bottom: 2rem;
}

.footer-logo {
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--text-primary);
}

.footer-brand p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-top: 0.25rem;
}

.footer-links-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.footer-col h4 {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    font-weight: 700;
}

.footer-col a {
    display: block;
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.9rem;
    padding: 0.25rem 0;
    transition: var(--transition);
}

.footer-col a:hover {
    color: var(--primary);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    font-size: 0.8rem;
    color: var(--text-muted);
}

.footer-legal {
    display: flex;
    gap: 1.5rem;
}

.footer-legal a {
    text-decoration: none;
    color: var(--text-muted);
    transition: var(--transition);
}

.footer-legal a:hover {
    color: var(--primary);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.375rem;
    margin-bottom: 1.5rem;
    color: var(--primary);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.9rem;
    padding: 0.4rem 0.8rem;
    border-radius: var(--radius-sm);
    transition: var(--transition);
}

.back-link:hover {
    background: rgba(99, 102, 241, 0.06);
}

/* ==========================================================================
   Animations
   ========================================================================== */

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

@keyframes pulse {
    0%, 100% { box-shadow: 0 0 0 0 rgba(99, 102, 241, 0.4); }
    50% { box-shadow: 0 0 0 12px rgba(99, 102, 241, 0); }
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(-2deg); }
    50% { transform: translateY(-16px) rotate(2deg); }
}

@keyframes pulse-scale {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.04); }
}

.operation-btn:active {
    animation: pulse-scale 0.2s ease-in-out;
}

/* ==========================================================================
   Responsive
   ========================================================================== */

@media (max-width: 768px) {
    .page-wrapper {
        padding: 0.75rem;
    }

    .header {
        padding: 2rem 1rem 1.5rem;
    }

    .logo h1 {
        font-size: 1.75rem;
    }

    .logo-icon {
        width: 44px;
        height: 44px;
    }

    .upload-area {
        padding: 2.5rem 1.25rem;
    }

    .progress-container {
        gap: 0.5rem;
    }

    .progress-arrow {
        display: none;
    }

    .features-grid,
    .formats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .hero-stats {
        gap: 1.5rem;
    }

    .stat-number {
        font-size: 1.4rem;
    }

    .floating-card {
        display: none;
    }

    .steps-grid {
        flex-direction: column;
    }

    .step-connector {
        transform: rotate(90deg);
    }

    .step-card {
        max-width: 100%;
    }

    .nav-links {
        display: none;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .convert-section,
    .progress-section,
    .download-section,
    .error-section {
        padding: 1.5rem 1rem;
    }

    .step-icon {
        width: 44px;
        height: 44px;
        font-size: 1.1rem;
    }

    .step-label {
        font-size: 0.7rem;
    }

    .features-grid,
    .formats-grid {
        grid-template-columns: 1fr;
    }
}

/* ==========================================================================
   Print
   ========================================================================== */

@media print {
    .ad-container,
    .ad-sidebar,
    .ad-sidebar-right,
    .theme-toggle {
        display: none !important;
    }

    .upload-section,
    .convert-section,
    .progress-section {
        display: none !important;
    }

    body::before {
        display: none;
    }
}